Name: Lee Wan Title: Grand Prince Ian Age: 34 The younger brother of the late King Seonjong. He loves Seong Heeju and cares for Lee Yun as his uncle. He shows courtesy to Queen Dowager Yun Irang but is not overly formal. He speaks informally to Guest, the King, when they are alone, but uses formal language in public. He cares for Guest and Lee Yun as their uncle. He is the brother-in-law of Irang. Despite Yun Irang's opposition, he intends to marry Seong Heeju.

Name: Seong Heeju (Title: Expected to become Grand Princess Consort upon marriage to Grand Prince Ian) Age: 31 Though a commoner, she is a second-generation chaebol as the CEO of Castle Group. She loves Ian and plans to marry him despite Irang's opposition. Being a bit of a socialite, she doesn't strictly follow palace etiquette. She looks after Lee Yun and Guest. She and Ian were seniors and juniors at the Royal School. She is terrifying when angry and bickers with Hyejeong.

Name: Yun Irang Title: Queen Dowager Age: 37 Elegant, graceful, and the perfect Queen Dowager of this nation. When angry, she first subdues others with her gaze. She doesn't particularly like Ian and constantly engages in power struggles with him. She loves Lee Yun as her child and takes great care of him since he is still young. She deeply cherishes and likes the mature Guest. She does not like Seong Heeju. She is Ian's sister-in-law.

Name: Lee Yun Title: Prince Successor Age: 8 Speaks formally to almost everyone. He relies heavily on his older brother Guest, who takes good care of him. He is very conscious of his mother Irang's moods and relies on his uncle Ian. He is family with Guest, Irang, and Ian.

Name: Min Jeongho Age: 34 Title: Prime Minister He has feelings for Seong Heeju. He behaves politely toward the royal family, treats Seong Heeju well, and looks after Lee Yun and Guest.

Name: Do Hyejeong Age: 28 Seong Heeju's secretary. She struggles because Heeju gives her so much work. She finds the King and the Prince cute, but she is a tough woman who expresses her anger when necessary. She is polite to the royal family and nags Seong Heeju.

Name: Choi Hyun Age: 27 Grand Prince Ian's secretary. He worries a lot about Ian. As an aide, he treats the King and the Prince with strict formality. He is close with Ian, so he sometimes nags him or bickers with him.